In many geographic areas of the United States, water supplied to homes from municipalities, water districts and wells contains a high level of impurities that render the water unpalatable for drinking and making ice cubes. Therefore reverse osmosis and carbon filter type water purification systems are used on a widespread basis.
Many refrigerators are equipped with door-mounted drinking water and ice dispensers. Purified water is often supplied to such refrigerators via Copper and plastic water supply lines from water filtration systems located under the kitchen sink. Some refrigerators, such as those sold under the GE® and HOTPOINT® brands, incorporate their own dedicated water filtration system of the type disclosed in U.S. Pat. No. 5,753,107 of Magnusson et al. They employ a removable filter cartridge sold under the SmartWater™ brand which is typically replaced about every three months. The filter cartridge is located in the interior of the refrigerator and mates with a manifold using a bayonet locking scheme. The cartridge has a female end with a large cylindrical cavity and a concentric small cylindrical cavity that depends from the large cylindrical cavity. The large and small cylindrical cavities of the female end of the filter cartridge provide mating surfaces that mate with correspondingly sized male cylindrical bodies of the manifold, which are surrounded by O-rings to provide water-tight seals. Water passes through a spring biased inlet valve of the water filtration system into the cylindrical filter cartridge. The inlet valve cooperates with the filter cartridge to prevent forward flow of water until the filter cartridge is properly seated on the manifold via insertion and twisting. Water then passes from the inlet valve, downwardly to the bottom of the filter cartridge, and then upwardly through a core of the filter cartridge that contains various filtration media. Filtered water then exits the filter cartridge back into the manifold and passes through an outlet check valve that prevents back flow. The filtered water is then delivered to the ice maker and to the water dispenser.
The SmartWater filter cartridges do not have any O-rings located adjacent their mating surfaces and therefore to ensure against leaks the water filtration system is totally dependent on the integrity of the O-rings that surround the male cylindrical bodies of the manifold to prevent water leakage. A slow leak in the water filtration system resulting from improper installation of the filer cartridge or failure of the O-rings that surround the male cylindrical bodies of the manifold may go unnoticed by the homeowner, leading to a large amount of water leaking into the refrigerator and eventually onto the floor of the kitchen when finally discovered. Replacement filter cartridges for the aforementioned GE and HOTPOINT refrigerators that are sold under the BRITA® brand have included an additional O-ring mounted in the large cylindrical cavity of the filter cartridge to provide additional sealing capability.